From 6a224221c469280361a899fa6b4cfab5de21b246 Mon Sep 17 00:00:00 2001
From: osolodo <andrew.wnfyc@gmail.com>
Date: Wed, 28 Mar 2018 16:19:15 +0100
Subject: [PATCH] Fixed serious bug in Matching

NOTE: it is important to understand that a null value matches and that
improper lists are used in matching to identify tail matching
---
 src/erl/asttrans.erl             | 13 +++-------
 src/js/classes/datatype_int.js   |  4 +--
 src/js/classes/datatype_list.js  | 44 ++++++++++++++++++++------------
 src/js/classes/datatype_tuple.js |  2 +-
 4 files changed, 35 insertions(+), 28 deletions(-)

diff --git a/src/erl/asttrans.erl b/src/erl/asttrans.erl
index 63b95c0..e4f4b42 100644
--- a/src/erl/asttrans.erl
+++ b/src/erl/asttrans.erl
@@ -785,13 +785,8 @@ recurse_var_assignments(ConsCount, {c_var, _, Name}, V, isTail) ->
             <<"=">>,
             estree:identifier(atom_to_binary(Name, utf8)),
             estree:call_expression(
-                estree:member_expression(V, estree:identifier(<<"slice">>), false),
-                [   estree:literal(ConsCount),
-                    estree:call_expression(
-                        estree:member_expression(V, estree:identifier(<<"size">>), false),
-                        []
-                    )
-                ]
+                estree:member_expression(V, estree:identifier(<<"nthSeg">>), false),
+                [estree:literal(ConsCount)]
             )
         )
     ];
@@ -802,13 +797,13 @@ recurse_var_assignments(_, {c_tuple, _, Elements}, V, _) ->
             lists:append(
                 L,
                 recurse_var_assignments(0, Elem,
-                    estree:expression_statement(
+                    %estree:expression_statement(
                         estree:call_expression(
                             estree:member_expression(V,
                                 estree:identifier(<<"nth">>), false),
                             [estree:literal(I)]
                         )
-                    ),
+                    ,%),
                     false
                 )
             )}
diff --git a/src/js/classes/datatype_int.js b/src/js/classes/datatype_int.js
index 182470d..6b04faf 100644
--- a/src/js/classes/datatype_int.js
+++ b/src/js/classes/datatype_int.js
@@ -15,8 +15,8 @@ const Int = (() => {
         }
 
         match(other) {
-            if (other===null||(!isNaN(other) && this.equals(other))) {
-                return other;
+            if (other==null||(!isNaN(other) && this.equals(other))) {
+                return this;
             }
             else {
                 return undefined;
diff --git a/src/js/classes/datatype_list.js b/src/js/classes/datatype_list.js
index c7f19bf..7c8c424 100644
--- a/src/js/classes/datatype_list.js
+++ b/src/js/classes/datatype_list.js
@@ -36,7 +36,7 @@ const List = (() => {
         [nthNode](n) {
             if (n < 0 || n >= this.size()) {
                 throw "index out of bounds error";
-            }    
+            }
         
             let i = 0;
             let walker = this;
@@ -58,7 +58,7 @@ const List = (() => {
                 next: () => {
                     // If the next node of the current iterator isn't another list OR is an empty list, then we know
                     // we have reached the end of the linked list
-                    let isLastNode = this.iterator.next === undefined || List.isEmptyList(this.iterator.next);
+                    let isLastNode = !this.iterator || this.iterator.next === undefined || List.isEmptyList(this.iterator.next);
                     let v = List.isList(this.iterator) ? this.iterator.value : this.iterator;
 
                     if (this.iterator === "done" || List.isEmptyList(this)) {
@@ -83,6 +83,10 @@ const List = (() => {
             return List.isList(nth) ? nth.value : nth;
         }
 
+        nthSeg(n){
+            return this[nthNode](n);
+        }
+
         size() {
             return [...this].length;
         }
@@ -128,21 +132,29 @@ const List = (() => {
         }
 
         match(other) {
-            if(other===null)return other;
-            if (List.isList(other) && this.size() === other.size()) {
-                for (let i = 0; i < this.size(); i++) {
-                    if (ErlangDatatype.isErlangDatatype(this.nth(i))) {
-                        if (this.nth(i).match(other.nth(i)) === undefined) {
-                            return undefined;
-                        }
-                    }
-                    else {
-                        if (this.nth(i) !== other.nth(i) && other.nth(i) !== null) {
-                            return undefined;
-                        }
-                    }
+            if(other===null)return this;
+            if (List.isList(other)) {
+
+                if(this.nth(0).match(other.nth(0))){//If the first values match
+                    if(other.next==null)return this;//Improper list (tail match)
+                    let a= this.next().match(other.next());
+                    if(a!=undefined) return this;
                 }
-                return other;
+                return undefined;
+                // for (let i = 0; i < this.size(); i++) {
+                //     if (ErlangDatatype.isErlangDatatype(this.nth(i))) {
+                //         if(other===null)return this;
+                //         if (this.nth(i).match(other.nth(i)) === undefined) {
+                //             return undefined;
+                //         }
+                //     }
+                //     else {
+                //         if (this.nth(i) !== other.nth(i) && other.nth(i) !== null) {
+                //             return undefined;
+                //         }
+                //     }
+                // }
+                // return other;
             }
             else {
                 return undefined;
diff --git a/src/js/classes/datatype_tuple.js b/src/js/classes/datatype_tuple.js
index fd36a31..800426d 100644
--- a/src/js/classes/datatype_tuple.js
+++ b/src/js/classes/datatype_tuple.js
@@ -92,7 +92,7 @@ const Tuple = (() => {
 
         match(other) {
             if(other===null)return other;
-            if (List.isTuple(other) && this.size() === other.size()) {
+            if (Tuple.isTuple(other) && this.size() === other.size()) {
                 for (let i = 0; i < this.size(); i++) {
                     if (ErlangDatatype.isErlangDatatype(this.nth(i))) {
                         if (this.nth(i).match(other.nth(i)) === undefined) {